Developmental toxicity of short-chain chlorinated paraffins on early-stage chicken embryos in a shell-less (ex-ovo) incubation system.

Short-chain chlorinated paraffins (SCCPs) are listed as a category of globally controlled persistent organic pollutants (POPs) by the Stockholm Convention in 2017. However, SCCP toxicity, particularly their developmental toxicity in avian embryos, has not been well studied. In this study, we observed the early development of chicken embryos (Gallus gallus domesticus) by applying a shell-less (ex-ovo) incubation system developed in our previous studies. After exposing embryos at Hamburger Hamilton stage (HHS) 1 to SCCPs (control, 0.1% DMSO; SCCPs-L, 200 ng/g; SCCPs-M, 2000 ng/g; SCCPs-H, 20,000 ng/g), we observed the development of embryos from the 3rd to 9th incubation day. Exposure to SCCPs-M and -H induced a significant reduction in survival, with an LD50 of 3100 ng/g on the 9th incubation day. Significant dose-dependent decreases in body length were observed from days 4-9. We also found that SCCPs-H decreased the blood vessel length and branch number on the 4th incubation day. Additionally, SCCPs-H significantly reduced the heart rate on the 4th and 5th incubation days. These findings suggest that SCCPs may have potential of developmental and cardiovascular toxicity during the early stages of chicken embryos. Quantitative PCR of the mRNA of genes related to embryonic development showed that SLC16A10 (a triiodothyronine transporter) level decreased in the SCCPs-H group, showing a significant positive correlation with the body length of embryos. THRA level, a thyroid hormone receptor, was significantly decreased in the SCCPs-H group, whereas that of DIO3 level, a deiodinase was significantly increased. These results suggest that SCCPs exposure induces developmental delays via the thyroxine signaling pathway. Analysis of thyroid hormones (THs) in blood plasma also indicated a significant reduction in thyroxine (T4) levels in the SCCPs-H group on the 9th incubation day of embryos. In conclusion, SCCPs induce developmental toxicity by disrupting thyroid functions at the early-life stage of chicken embryos.

Association between prenatal exposure to persistent organic pollutants and neurodevelopment in early life: A mother-child cohort (Shanghai, China).

As common environmental pollutants, persistent organic pollutants (POPs) that are widely applied in industry and agriculture have adverse effects on neurodevelopment. However, evidence on the neurotoxicity of POPs in neural development of offspring is limited. This study explored the relationship between prenatal exposure to POPs and neurodevelopment of 18-month-old toddlers in a mother-child cohort in Shanghai, China. In this study, we determined exposure levels of 37 POPs in cord blood serum collected at the time of delivery. The detection rate of pollutants HCB, ß-HCH, and p,p'-DDE was higher than 60%, so these will be discussed in the following analysis. From birth to approximately 18 months, we followed up infants to longitudinally explore whether POPs influenced their language, motor, and cognitive development according to a Bayley-Ⅲ assessment . Based on multivariable regression analyses, the ß-HCH concentration in cord serum was negatively related to motor development scores in children at 18 months by adjusting for the covariates, but there was no change in language and cognition. Further piecewise linear regression analysis showed that a cord serum ß-HCH concentration greater than 0.2 µg/L had a significantly negative correlation with the motor development scores. p,p'-DDE was positively associated with language development at 18 months before and after adjusting for covariates. But prenatal HCB levels were not associated with any of the Bayley-Ⅲ subscales at 18 months. We concluded that prenatal exposure to ß-HCH might have adverse effects on infants' motor development. The minimum harmful concentration of ß-HCH was estimated at 0.2 µg/L in cord serum. The unexpected positive association between p,p'-DDT and language development could be due to live birth bias.

Blood screening for heavy metals and organic pollutants in cancer patients exposed to toxic waste in southern Italy: A pilot study.

In Italy, in the eastern area of the Campania region, the illegal dumping and burning of waste have been documented, which could potentially affect the local population's health. In particular, toxic waste exposure has been suggested to associate with increased cancer development/mortality in these areas, although a causal link has not yet been established. In this pilot study, we evaluated blood levels of toxic heavy metals and persistent organic pollutants (POPs) in 95 patients with different cancer types residing in this area and in 27 healthy individuals. While we did not find any significant correlation between the blood levels of POPs and the provenance of the patients, we did observe high blood concentrations of heavy metals in some municipalities, including Giugliano, where many illegal waste disposal sites have previously been documented. Our results showed that patients with different cancer types from Giugliano had higher blood levels of heavy metals than healthy controls. Despite the obvious limitations of this exploratory study, our preliminary observations encourage further research assessing the possible association between exposure to hazardous waste, increased blood metals, and increased risk of cancer.

The action of low doses of persistent organic pollutants (POPs) on mitochondrial function in zebrafish eyes and comparison with hyperglycemia to identify a link between POPs and diabetes.

Type 2 diabetes (T2D) is characterized by defects in insulin action to target tissues, resulting in hyperglycemia, insulin resistance, and mitochondrial dysfunction. The eye is one of the organs susceptible to T2D, but knowledge regarding mitochondrial dysfunction in the eyes after hyperglycemia and T2D is based mainly on epidemiological evidence, with little experimental data. Persistent organic pollutants (POPs) are known as endocrine-disrupting chemicals and are associated with uncontrolled glucose and lipid metabolism, leading to the onset of diabetes. To determine the relationship between POPs and T2D, two model systems were developed: glucose-immersed zebrafish to induce hyperglycemia, and zebrafish exposed to low-dose POPs in a water circulating system for three months. To examine the role of mitochondrial function, the activity of mitochondrial complexes I, II, III, and IV from the eyes of the two zebrafish models was measured spectrophotometrically. Enhanced enzymatic activities of mitochondrial complexes III and IV were observed in the eyes of both hyperglycemia and low-dose POPs exposed models, especially in male zebrafish. These results demonstrate that POPs alleviate mitochondrial oxidative phosphorylation (OXPHOS) in a sex-dependent manner through a compensatory mechanism, which is also observed in acute hyperglycemia.

Personalized mixture toxicity testing: A proof-of-principle in vitro study evaluating the steroidogenic effects of reconstructed contaminant mixtures measured in blood of individual adults.

Chemical risk assessments typically focus on single substances, often overlooking real-world co-exposures to chemical mixtures. Mixture toxicology studies using representative mixtures can reveal potential chemical interactions, but these do not account for the unique chemical profiles that occur in the blood of diverse individuals. Here we used the H295R steroidogenesis assay to screen personalized mixtures of 24 persistent organic pollutants (POPs) for cytotoxicity and endocrine disruption. Each mixture was reconstructed at a human exposure relevant concentration (1×), as well as at 10- and 100-fold higher concentration (10×, 100×) by acoustic liquid handling based on measured blood concentrations in a Swedish cohort. Among the twelve mixtures tested, nine mixtures decreased the cell viability by 4-18%, primarily at the highest concentration. While the median and maximum mixtures based on the whole study population induced no measurable effects on steroidogenesis at any concentration, the personalized mixture from an individual with the lowest total POPs concentration was the only mixture that affected estradiol synthesis (35% increase at the 100× concentration). Mixtures reconstructed from blood levels of three different individuals stimulated testosterone synthesis at the 1× (11-15%) and 10× concentrations (12-16%), but not at the 100× concentration. This proof-of-principle personalized toxicity study illustrates that population-based representative chemical mixtures may not adequately account for the toxicological risks posed to individuals. It highlights the importance of testing a range of real-world mixtures at relevant concentrations to explore potential interactions and non-monotonic effects. Further toxicological studies of personalized contaminant mixtures could improve chemical risk assessment and advance the understanding of human health, as chemical exposome data become increasingly available.

Unveiling the ecotoxicological impact of microplastics on organisms - the persistent organic pollutant (POP): A comprehensive review.

Microplastics have been ubiquitous in our environment for decades, and numerous studies have revealed their extensive dispersion, reaching far beyond the surface of the land, soil, aquatic ecosystems. They have infiltrated the food-chain, the food web, even the air we breathe, as well as the water we drink. Microplastics have been detected in the food we consume, acting as vectors for hazardous chemicals that adhere to their hydrophobic surfaces. This can result in the transfer of these chemicals to the aquatic life, posing a threat to their well-being. The release of microplastics into different environmental settings can give rise to various eco-toxicological implications. The substantial body of literature has led scientists to the consensus that microplastic pollution is a global problem with the potential to impact virtually any type of ecosystem. This paper aims to discuss crucial information regarding the occurrence, accumulation, and ecological effects of microplastics on organisms. It also highlights the new and emerging disease named "Plasticosis" that is directly linked to microplastics and its toxicological effects like permanent scarring and long-term inflammation in the digestive system of the seabirds. By comprehending the behaviour of these microplastic pollutants in diverse habitats and evaluating their ecological consequences, it becomes possible to facilitate a better understanding of this toxicological issue.

Effects of persistent organic pollutants on telomere dynamics are sex and age-specific in a wild long-lived bird.

Chemical pollution is a major man-made environmental threat to ecosystems and natural animal populations. Of concern are persistent organic pollutants (POPs), which can persist in the environment for many years. While bioaccumulating throughout the lives of wild animals, POPs can affect their health, reproduction, and survival. However, measuring long-term effects of POPs in wild populations is challenging, and therefore appropriate biomarkers are required in wildlife ecotoxicology. One potential target is telomere length, since telomere preservation has been associated to survival and longevity, and stressors as chemical pollution can disrupt its maintenance. Here, we investigated the effects of different classes of POPs on relative telomere length (RTL) and its rate of change (TROC) in wild long-lived Alpine swifts (Tachymarptis melba). As both RTL and TROC are often reported to differ between sexes and with chronological age, we tested for sex- and age-specific (pre-senescent vs. senescent, ≥ 9 age of years, individuals) effects of POPs. Our results showed that senescent females presented longer RTL and elongated telomeres over time compared to pre-senescent females and males. These sex- and age-related differences in RTL and TROC were influenced by POPs, but differently depending on whether they were organochlorine pesticides (OCPs) or industrial polychlorinated biphenyls (PCBs). OCPs (particularly drins) were negatively associated with RTL, with the strongest negative effects being found in senescent females. Conversely, PCBs led to slower rates of telomere shortening, especially in females. Our study indicates diametrically opposed effects of OCPs on RTL and PCBs on TROC, and these effects were more pronounced in females and senescent individuals. The mechanisms behind these effects (e.g., increased oxidative stress by OCPs; upregulation of telomerase activity by PCBs) remain unknown. Our results highlight the importance in wildlife ecotoxicology to account for sex- and age-related effects when investigating the health effects of pollutants on biomarkers such as telomeres.

Effects of PFAS on human liver transporters: implications for health outcomes.

Per- and polyfluoroalkyl substances (PFAS) have become internationally recognized over the past three decades as persistent organic pollutants used in the production of various consumer and industrial goods. Research efforts continue to gauge the risk that historically used, and newly produced, PFAS may cause to human health. Numerous studies report toxic effects of PFAS on the human liver as well as increased serum cholesterol levels in adults. A major concern with PFAS, also dubbed "forever chemicals," is that they accumulate in the liver and kidney and persist in serum. The mechanisms responsible for their disposition and excretion in humans are poorly understood. A better understanding of the interaction of PFAS with liver transporters, as it pertains to the disposition of PFAS and other xenobiotics, could provide mechanistic insight into human health effects and guide efforts toward risk assessment of compounds in development. This review summarizes the current state of the literature on the emerging relationships (eg, substrates, inhibitors, modulators of gene expression) between PFAS and specific hepatic transporters. The adaptive and toxicological responses of hepatocytes to PFAS that reveal linkages to pathologies and epidemiological findings are highlighted. The evidence suggests that our understanding of the molecular landscape of PFAS must improve to determine their impact on the expression and function of hepatocyte transporters that play a key role in PFAS or other xenobiotic disposition. From here, we can assess what role these changes may have in documented human health outcomes.

Exposure to Endocrine Disruptors in Early life and Neuroimaging Findings in Childhood and Adolescence: a Scoping Review.

PURPOSE OF REVIEW: Evidence suggests neurotoxicity of endocrine disrupting chemicals (EDCs) during sensitive periods of development. We present an overview of pediatric population neuroimaging studies that examined brain influences of EDC exposure during prenatal period and childhood. RECENT FINDINGS: We found 46 studies that used magnetic resonance imaging (MRI) to examine brain influences of EDCs. These studies showed associations of prenatal exposure to phthalates, organophosphate pesticides (OPs), polyaromatic hydrocarbons and persistent organic pollutants with global and regional brain structural alterations. Few studies suggested alteration in functional MRI associated with prenatal OP exposure. However, studies on other groups of EDCs, such as bisphenols, and those that examined childhood exposure were less conclusive. These findings underscore the potential profound and lasting effects of prenatal EDC exposure on brain development, emphasizing the need for better regulation and strategies to reduce exposure and mitigate impacts. More studies are needed to examine the influence of postnatal exposure to EDC on brain imaging.

Innovate beyond PFAS.

New proposed legislation on "forever" chemicals is under consideration in Europe and the United States, where per- and polyfluoroalkyl substances (PFAS) are a hot topic for regulators and lawmakers. On both sides of the Atlantic, regulation of widely used PFAS has been complex and evolving. Their presence in hundreds of different products-from nonstick cookware to food packaging to firefighting foam-and their persistence in food, drinking water, and the environment have resulted in a pollution problem of unprecedented scale. Recently, for example, it was reported that 45% of the tap water in the United States contains at least one type of PFAS. Because these compounds are so chemically stable that they do not degrade in the environment (including in the human body), PFAS seriously challenge long-established ideas of how chemicals can be used, assessed, and regulated, and it remains to be seen whether the new regulations will solve this problem.

The relationship between dietary exposure to persistent organic pollutants from fish consumption and type 2 diabetes among First Nations in Canada.

OBJECTIVE: We previously examined the associations between dietary dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) intake from fish consumption and type 2 diabetes (T2D) prevalence in Ontario and Manitoba. This study aims to further explore the relationship in a regionally representative sample of First Nations adults living on-reserve across Canada. METHODS: Dietary, health and lifestyle data collected by the cross-sectional First Nations Food, Nutrition and Environment Study (2008-2018) were analyzed. This participatory study included 6091 First Nations adult participants who answered questions on T2D. The consumption of locally caught fish was estimated with a food frequency questionnaire. A total of 551 samples from 96 fish species were collected and analyzed for the presence of DDE and PCBs. The associations between fish and dietary DDE/PCBs intake with self-reported T2D were investigated using multiple logistic regression models adjusted for confounders. RESULTS: Dietary exposure to DDE (>2.11 ng/kg/bw) and PCBs (>1.47 ng/kg/bw) vs no exposure was positively associated with T2D with ORs of 2.33 (95% CI: 1.24-4.35) for DDE and 1.43 (95% CI: 1.01-3.59) for PCBs. The associations were stronger among females (DDE OR = 3.11 (1.41-6.88); PCBs OR = 1.76 (1.10-3.65)) and older individuals (DDE OR = 2.64 (1.12-6.20); PCBs OR = 1.44 (1.01-3.91)) as compared with males and younger participants. Also, significant dose-response relationships were found for fish consumption in females only. CONCLUSION: This study confirms our previous findings that dietary DDE/PCBs exposure may increase the risk of T2D. The effect of DDE/PCBs from fish consumption is driven by geographical differences in DDE/PCBs concentrations in fish and by the amount of fish consumed, and is more prominent in females than in males.

RéSUMé: OBJECTIF: Nous avons précédemment examiné les associations entre l'apport alimentaire de dichlorodiphényldichloroéthylène (DDE) et de polychlorobiphényles (PCB) provenant de la consommation de poisson et la prévalence du diabète de type 2 (DT2) en Ontario et au Manitoba. Cette étude vise à explorer davantage la relation dans un échantillon régionalement représentatif d'adultes des Premières Nations vivant dans des réserves partout au Canada. MéTHODE: Les données sur l'alimentation, la santé et le mode de vie recueillies par l'Étude transversale sur l'alimentation, la nutrition et l'environnement chez les Premières Nations (2008­2018) ont été analysées. Cette étude participative comprenait 6 091 participants adultes des Premières Nations qui ont répondu à des questions sur le DT2. La consommation de poisson pêché localement a été estimée à l'aide d'un questionnaire de fréquence alimentaire. Au total, 551 échantillons de 96 espèces de poissons ont été prélevés et analysés pour la présence de DDE et de PCB. Les associations entre la consommation de poisson et l'exposition aux DDE/PCB avec le DT2 auto-déclaré ont été étudiées à l'aide de modèles de régression logistique multiples ajustés pour les facteurs de confusion. RéSULTATS: L'exposition alimentaire au DDE (>2,11 ng/kg/pc) et aux PCB (>1,47 ng/kg/pc) par rapport à l'absence d'exposition était positivement associée au DT2 avec des OR de 2,33 (IC à 95% : 1,24­4,35) pour le DDE et 1,43 (IC à 95% : 1,01­3,59) pour les PCB. Les associations étaient plus fortes chez les femmes (DDE OR = 3,11 (1,41­6,88); PCB OR = 1,76 (1,10­3,65)) et les individus plus âgés (DDE OR = 2,64 (1,12­6,20); PCB OR = 1,44 (1,01­3,91)) par rapport aux hommes et aux participants plus jeunes. De plus, des relations dose-réponse significatives ont été trouvées pour la consommation de poisson chez les femmes seulement. CONCLUSION: Cette étude confirme nos conclusions précédentes selon lesquelles l'exposition à travers l'alimentation aux DDE/PCB peut augmenter le risque de DT2. L'effet du DDE/PCB sur la consommation de poisson est lié aux différences géographiques dans les concentrations de DDE/PCB dans le poisson et à la quantité de poisson consommée, et est plus important chez les femmes que chez les hommes.

Exploring the binding mechanism and adverse toxic effects of persistent organic pollutant (dicofol) to human serum albumin: A biophysical, biochemical and computational approach.

The organochlorine pesticide dicofol (DCF), a persistent organic pollutant, is used as acaricide worldwide. Considering its large consumption in the agriculture sector and potential toxic effects such as endocrine disruption, carcinogenicity, and environmental persistence are detrimental to human health. To take an extensive evaluation of its potential toxicity, the current study was aimed to explore the binding mechanism and adverse effect of DCF on human serum albumin (HSA) by using an array of biophysical techniques (UV-visible, fluorescence, 3D fluorescence, and circular dichroism spectroscopy), isothermal titration calorimetric (ITC), computational methods and biochemical approaches. Fluorescence quenching and UV-Visible spectra of the HSA-DCF system confirmed static quenching mechanism and complex formation between HSA and DCF. The thermodynamics results from ITC revealed DCF-HSA interaction was exothermic and spontaneous and involved hydrophobic interactions and hydrogen bonding. The esterase activity of HSA displayed constant Vmax and elevated Km values confirming DCF-HSA competitive interaction. Circular dichroism spectra results revealed structural changes in HSA protein on interaction with DCF. Furthermore, molecular-specific site marker and molecular modelling results affirmed that the binding Site of DCF is Site I of HSA. A significant carbonyl content level in DCF-HSA system suggested protein structure damage. This work is likely to add a better understanding of DCF toxicity in human health and helpful in fortifying the check on food safety.

A mixture of persistent organic pollutants detected in human follicular fluid increases progesterone secretion and mitochondrial activity in human granulosa HGrC1 cells.

Disruption of granulosa cells (GCs), the main functional cells in the ovary, is associated with impaired female fertility. Epidemiological studies demonstrated that women have detectable levels of organic pollutants (e.g., perfluorooctanoate, perfluorooctane sulfonate, 2,2-dichlorodiphenyldichloroethylene, polychlorinated biphenyl 153, and hexachlorobenzene) in their follicular fluid (FF), and thus these compounds may directly affect the function of GCs in the ovary. Considering that humans are exposed to multiple pollutants simultaneously, we elucidated the effects of a mixture of endocrine-disrupting chemicals (EDCs) on human granulosa HGrC1 cells. The EDC mixture directly increased progesterone secretion by upregulating 3ß-hydroxysteroid dehydrogenase (3ßHSD) expression. Furthermore, the EDC mixture increased activity of mitochondria, which are the central sites for steroid hormone biosynthesis, and the ATP content. Unexpectedly, the EDC mixture reduced glucose transporter 4 (GLUT4) expression and perturbed glucose uptake; however, this did not affect the glycolytic rate. Moreover, inhibition of GLUT1 by STF-31 did not alter the effects of the EDC mixture on steroid secretion but decreased basal estradiol secretion. Taken together, our results demonstrate that the mixture of EDCs present in FF can alter the functions of human GCs by disrupting steroidogenesis and may thus adversely affect female reproductive health. This study highlights that the EDC mixture elicits its effects by targeting mitochondria and increases mitochondrial network formation, mitochondrial activity, and expression of 3ßHSD, which is associated with the inner mitochondrial membrane.

Perinatal exposure to a human relevant mixture of persistent organic pollutants: Effects on mammary gland development, ovarian folliculogenesis and liver in CD-1 mice.

The ability of persistent organic pollutants (POPs) with endocrine disrupting properties to interfere with the developing reproductive system is of increasing concern. POPs are transferred from dams to offspring and the high sensitivity of neonates to endocrine disturbances may be caused by underdeveloped systems of metabolism and excretion. The present study aimed to characterize the effect of in utero and lactational exposure to a human relevant mixture of POPs on the female mammary gland, ovarian folliculogenesis and liver function in CD-1 offspring mice. Dams were exposed to the mixture through the diet at Control, Low or High doses (representing 0x, 5000x and 100 000x human estimated daily intake levels, respectively) from weaning and throughout mating, gestation, and lactation. Perinatally exposed female offspring exhibited altered mammary gland development and a suppressed ovarian follicle maturation. Increased hepatic cytochrome P450 enzymatic activities indirectly indicated activation of nuclear receptors and potential generation of reactive products. Hepatocellular hypertrophy was observed from weaning until 30 weeks of age and could potentially lead to hepatotoxicity. Further studies should investigate the effects of human relevant mixtures of POPs on several hormones combined with female reproductive ability and liver function.

Exposure to human relevant mixtures of halogenated persistent organic pollutants (POPs) alters neurodevelopmental processes in human neural stem cells undergoing differentiation.

Halogenated persistent organic pollutants (POPs) like perfluorinated alkylated substances (PFASs), brominated flame retardants (BFRs), organochlorine pesticides and polychlorinated biphenyls (PCBs) are known to cause cancer, immunotoxicity, neurotoxicity and interfere with reproduction and development. Concerns have been raised about the impact of POPs upon brain development and possibly neurodevelopmental disorders. The developing brain is a particularly vulnerable organ due to dynamic and complex neurodevelopmental processes occurring early in life. However, very few studies have reported on the effects of POP mixtures at human relevant exposures, and their impact on key neurodevelopmental processes using human in vitro test systems. Aiming to reduce this knowledge gap, we exposed mixed neuronal/glial cultures differentiated from neural stem cells (NSCs) derived from human induced pluripotent stem cells (hiPSCs) to reconstructed mixtures of 29 different POPs using concentrations comparable to Scandinavian human blood levels. Effects of the POP mixtures on neuronal proliferation, differentiation and synaptogenesis were evaluated using in vitro assays anchored to common key events identified in the existing developmental neurotoxicity (DNT) adverse outcome pathways (AOPs). The present study showed that mixtures of POPs (in particular brominated and chlorinated compounds) at human relevant concentrations increased proliferation of NSCs and decreased synapse number. Based on a mathematical modelling, synaptogenesis and neurite outgrowth seem to be the most sensitive DNT in vitro endpoints. Our results indicate that prenatal exposure to POPs may affect human brain development, potentially contributing to recently observed learning and memory deficits in children.

Mixtures of persistent organic pollutants increase ovarian granulosa tumor cell line migration and spheroid invasion by upregulating MMP2 expression and activity via IGF1R.

Granulosa cell tumors (GCT) of the ovary have a good prognosis. Recurrence tends to be late; however, > 66 % of patients with recurrent GCT die from the disease. Most recurrences are abdominopelvic, although distant metastases have been documented. Here, we tested the hypothesis that a mixture of persistent endocrine-disrupting chemicals (EDCs) stimulates the invasion of GCT cells. We selected perfluorooctanoate (PFOA, 2 ng/mL), perfluorooctanesulfonate (PFOS, 8 ng/mL), 2,2-dichlorodiphenyldichloroethylene (p,p'-DDE, 1 ng/mL), polychlorinated biphenyl 153 (PCB153, 100 pg/mL), and hexachlorobenzene (HCB, 50 pg/mL), which have the highest measured concentrations in follicular fluid of women undergoing treatment with assisted reproductive technology. The human GCT cell lines COV434 and KGN have been used as in vitro models of juvenile (JGCT) and adult (AGCT) GCT subtypes, respectively. Cells were treated with a mixture of the test compounds for 15 min prior to analysis of protein phosphorylation; for 4 h prior to analysis in a circular chemorepellent-induced defect assay; for 6 h prior to analysis of matrix metalloproteinase 2 (MMP2) activity; for 24 h prior to analysis of migration, invasion, and gene expression; and for 48 h prior to analysis of protein expression. First, we showed that KGN cells migrated and exhibited invasive behavior. By contrast, COV434 cells lacked migration and invasion potential. Moreover, expression of mesenchymal genes and the gene encoding MMP2 was higher in KGN cells, and that of epithelial genes lower, than that in COV434 cells. Treatment of KGN cells with the EDC mixture stimulated cell migration, invasion, and lymphatic dissemination. The results suggest that the role of the EDC mixture in AGCT invasion is not related to changes in expression of epithelial and mesenchymal genes; rather, it is related to increased expression and activity of MMP2. Additionally, silencing insulin-like growth factor 1 (IGF1R) in AGCT abolished the stimulatory effect of the EDC mixture on KGN spheroid invasion. These results demonstrate that the EDC mixture increased KGN spheroid invasion by stimulating expression and activity of MMP2 via IGF1R.

A human relevant mixture of persistent organic pollutants (POPs) and perfluorooctane sulfonic acid (PFOS) differentially affect glutamate induced excitotoxic responses in chicken cerebellum granule neurons (CGNs) in vitro.

Primary cultures of cerebellar granule neurons (CGNs) derived from chicken embryos were used to explore the effects on developmental neurotoxicity by a complex defined mixture of persistent organic pollutants (POPs). Its chemical composition and concentrations were based on blood levels in the Norwegian/Scandinavian population. Perfluorooctane sulfonic acid (PFOS) alone, its most abundant compound was also evaluated. Different stages of CGNs maturation, between day in vitro (DIV) 1, 3, and 5 were exposed to the POP mixture, or PFOS alone. Their combination with glutamate, an excitatory endogenous neurotransmitter important in neurodevelopment, also known to cause excitotoxicity was evaluated. Outcomes with the mixture at 500x blood levels were compared to PFOS at its corresponding concentration of 20 µM. The POP mixture reduced tetrazolium salt (MTT) conversion at earlier stages of maturation, compared to PFOS alone. Glutamate-induced excitotoxicity was enhanced above the level of that induced by glutamate alone, especially in mature CGNs at DIV5. Glutathione (GSH) concentrations seemed to set the level of sensitivity for the toxic insults from exposures to the pollutants. The role of N-methyl-D-aspartate receptor (NMDA-R) mediated calcium influx in pollutant exposures was investigated using the non-competitive and competitive receptor antagonists MK-801 and CGP 39551. Observations indicate a calcium-independent, but still NMDA-R dependent mechanism in the absence of glutamate, and a calcium- and NMDA-R dependent one in the presence of glutamate. The outcomes for the POP mixture cannot be explained by PFOS alone, indicating that other chemicals in the mixture contribute its overall effect.

Computational systems biology as an animal-free approach to characterize toxicological effects of persistent organic pollutants.

Exposure to persistent organic pollutants (POPs), as defined by the Stockholm Convention, may alter biological systems and cause toxic effects. Computational studies appear to be a relevant approach to increase our understanding of the molecular mechanisms triggered by POPs. We investigated the use of a systems toxicology approach to explore the effects of POPs on human health. A protein-protein association network (PPAN) was developed based on known POP-protein interactions. This model was used to predict protein complexes for several candidate POPs, including dicofol, methoxychlor, and perfluorooctanoic acid (PFOA), that are listed or proposed to be listed as POPs by the Stockholm Convention. Integration of multiple data sources (pathways, disease annotations, adverse outcome pathways) involving the identified protein complexes was performed independently in order to reveal putative risk factors for human health. This approach revealed that several systems may be disturbed by these candidate POPs, mainly the reproductive, metabolic and nervous systems. This study highlights that a computational systems toxicology approach may help to decipher putative biological mecha­nisms of poorly studied chemicals and link them to possible adverse effects with the aim to support regulatory assessment and trigger new epidemiological and experimental studies. In order to develop more accurate computational models as alternative methods to animal testing, the next challenge will be to integrate more data according to the findable, acces­sible, interoperable and reusable (FAIR) data principles.

Concentrations of persistent organic pollutants in maternal plasma and epigenome-wide placental DNA methylation.

BACKGROUND: Prenatal maternal plasma persistent organic pollutant (POP) concentrations have been associated with neonatal outcomes. However, the underlying mechanisms remain unknown. Placental epigenetic mechanisms may be involved, but no prior epigenome-wide studies have investigated the impact of maternal POPs on placental DNA methylation. We studied the association between maternal plasma POP concentration in early pregnancy and epigenome-wide placental DNA methylation among 260 pregnant women from the NICHD Fetal Growth Studies. RESULTS: Our analysis focused on POPs with more than 80% plasma concentrations above the limit of quantification, including 3 organochlorine pesticides (hexachlorobenzene, trans-nonachlor, p,p'-dichlorodiphenyldichloroethylene), 1 polybrominated diphenyl ether (PBDE 47), 3 polychlorinated biphenyls (138/158, 153, 180), and 6 poly- and perfluorinated alkyl substances (PFASs) (perfluorodecanoic acid, perfluorohexanesulfonic acid, perfluorononanoic acid, perfluorooctanesulfonic acid, perfluoroundecanoic acid (PFUnDA)). Using 5% false discovery rate, POPs were associated with a total of 214 differentially methylated CpG sites (nominal p values ranging from 2.61 × 10-21 to 2.11 × 10-7). Out of the 214 CpG sites, 24 (11%) were significantly correlated with placental expression of 21 genes. Notably, higher PFUnDA was associated with increased methylation at 3 CpG sites (cg13996963, cg12089439, cg18145877) annotated to TUSC3, and increased methylation at those 3 CpG sites was correlated with decreased expression of TUSC3 in the placenta. Increased methylation at cg18145877 (TUSC3) and decreased expression of TUSC3 were correlated with shorter birth length. Out of the 214 CpG sites, methylation at 44 CpG sites was correlated (p value < 0.10) with at least one neonatal anthropometry measure (i.e., birth weight, birth length, and head circumference). Seven CpG sites mediated (p value < 0.05) the association between PBDE 47 and neonatal anthropometry measures. Genes annotating the top differentially methylated CpG sites were enriched in pathways related to differentiation of embryonic cells (PBDE 47) and in pathways related to brain size and brain morphology (PFASs). CONCLUSIONS: DNA methylation changes in the placenta were significantly associated with maternal plasma POPs concentration. The findings suggest that placental DNA methylation and gene expression mechanism may be involved in the prenatal toxicity of POPs and their association with neonatal anthropometry measures.

Environment-friendly PCN derivatives design and environmental behavior simulation based on a multi-activity 3D-QSAR model and molecular dynamics.

A multi-activity three-dimensional quantitative structure-activity relationship (3D-QSAR) model was established based on the comprehensive evaluation index (CEI) of polychlorinated naphthalenes (PCNs). The CEI values were calculated using the vector analysis method in combination with the following parameters: biological toxicity (predicted by logEC50), bioconcentration (predicted by logKow), long-distance migration (predicted by logPL), and biodegradation (predicted by total-score). Additionally, sixty-four CN-70 derivatives with lower CEI values were designed, among which three derivatives with reduced CEI values were selected for verification based on an evaluation of their persistent organic pollutant properties and practicability. Finally, an environmental behavior simulation was conducted via molecular dynamics simulation aided by the Taguchi experimental design by considering the degradation characteristics of the three aforementioned CN-70 derivatives as an example. Only two of the selected CN-70 derivatives were observed to be more easily degraded when compared with the CN-70 molecule (ascending range: 11.57 %-13.57 %) in a real-world setting, which was consistent with the biodegradability prediction results (ascending range: 14.94 %-22.49 %) obtained through the molecular docking studies. The multi-activity 3D-QSAR model established in this study overcame the limitations of generating molecular designs based on single-effect models from the source because it focused on the multiple effects of the pollutants.